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package p2p
import (
"context"
"fmt"
"net"
"time"
"github.com/tendermint/tendermint/config"
"github.com/tendermint/tendermint/crypto"
"github.com/tendermint/tendermint/p2p/conn"
)
const (
defaultDialTimeout = time.Second
defaultFilterTimeout = 5 * time.Second
defaultHandshakeTimeout = 3 * time.Second
)
// IPResolver is a behaviour subset of net.Resolver.
type IPResolver interface {
LookupIPAddr(context.Context, string) ([]net.IPAddr, error)
}
// accept is the container to carry the upgraded connection and NodeInfo from an
// asynchronously running routine to the Accept method.
type accept struct {
conn net.Conn
nodeInfo NodeInfo
err error
}
// peerConfig is used to bundle data we need to fully setup a Peer with an
// MConn, provided by the caller of Accept and Dial (currently the Switch). This
// a temporary measure until reactor setup is less dynamic and we introduce the
// concept of PeerBehaviour to communicate about significant Peer lifecycle
// events.
// TODO(xla): Refactor out with more static Reactor setup and PeerBehaviour.
type peerConfig struct {
chDescs []*conn.ChannelDescriptor
onPeerError func(Peer, interface{})
outbound, persistent bool
reactorsByCh map[byte]Reactor
metrics *Metrics
}
// Transport emits and connects to Peers. The implementation of Peer is left to
// the transport. Each transport is also responsible to filter establishing
// peers specific to its domain.
type Transport interface {
// Accept returns a newly connected Peer.
Accept(peerConfig) (Peer, error)
// Dial connects to the Peer for the address.
Dial(NetAddress, peerConfig) (Peer, error)
}
// transportLifecycle bundles the methods for callers to control start and stop
// behaviour.
type transportLifecycle interface {
Close() error
Listen(NetAddress) error
}
// ConnFilterFunc to be implemented by filter hooks after a new connection has
// been established. The set of exisiting connections is passed along together
// with all resolved IPs for the new connection.
type ConnFilterFunc func(ConnSet, net.Conn, []net.IP) error
// ConnDuplicateIPFilter resolves and keeps all ips for an incoming connection
// and refuses new ones if they come from a known ip.
func ConnDuplicateIPFilter() ConnFilterFunc {
return func(cs ConnSet, c net.Conn, ips []net.IP) error {
for _, ip := range ips {
if cs.HasIP(ip) {
return ErrRejected{
conn: c,
err: fmt.Errorf("IP<%v> already connected", ip),
isDuplicate: true,
}
}
}
return nil
}
}
// MultiplexTransportOption sets an optional parameter on the
// MultiplexTransport.
type MultiplexTransportOption func(*MultiplexTransport)
// MultiplexTransportConnFilters sets the filters for rejection new connections.
func MultiplexTransportConnFilters(
filters ...ConnFilterFunc,
) MultiplexTransportOption {
return func(mt *MultiplexTransport) { mt.connFilters = filters }
}
// MultiplexTransportFilterTimeout sets the timeout waited for filter calls to
// return.
func MultiplexTransportFilterTimeout(
timeout time.Duration,
) MultiplexTransportOption {
return func(mt *MultiplexTransport) { mt.filterTimeout = timeout }
}
// MultiplexTransportResolver sets the Resolver used for ip lokkups, defaults to
// net.DefaultResolver.
func MultiplexTransportResolver(resolver IPResolver) MultiplexTransportOption {
return func(mt *MultiplexTransport) { mt.resolver = resolver }
}
// MultiplexTransport accepts and dials tcp connections and upgrades them to
// multiplexed peers.
type MultiplexTransport struct {
listener net.Listener
acceptc chan accept
closec chan struct{}
// Lookup table for duplicate ip and id checks.
conns ConnSet
connFilters []ConnFilterFunc
dialTimeout time.Duration
filterTimeout time.Duration
handshakeTimeout time.Duration
nodeInfo NodeInfo
nodeKey NodeKey
resolver IPResolver
// TODO(xla): Those configs are still needed as we parameterise peerConn and
// peer currently. All relevant configuration should be refactored into options
// with sane defaults.
mConfig conn.MConnConfig
p2pConfig config.P2PConfig
}
// Test multiplexTransport for interface completeness.
var _ Transport = (*MultiplexTransport)(nil)
var _ transportLifecycle = (*MultiplexTransport)(nil)
// NewMultiplexTransport returns a tcp connected multiplexed peer.
func NewMultiplexTransport(
nodeInfo NodeInfo,
nodeKey NodeKey,
) *MultiplexTransport {
return &MultiplexTransport{
acceptc: make(chan accept),
closec: make(chan struct{}),
dialTimeout: defaultDialTimeout,
filterTimeout: defaultFilterTimeout,
handshakeTimeout: defaultHandshakeTimeout,
mConfig: conn.DefaultMConnConfig(),
nodeInfo: nodeInfo,
nodeKey: nodeKey,
conns: NewConnSet(),
resolver: net.DefaultResolver,
}
}
// Accept implements Transport.
func (mt *MultiplexTransport) Accept(cfg peerConfig) (Peer, error) {
select {
// This case should never have any side-effectful/blocking operations to
// ensure that quality peers are ready to be used.
case a := <-mt.acceptc:
if a.err != nil {
return nil, a.err
}
cfg.outbound = false
return mt.wrapPeer(a.conn, a.nodeInfo, cfg), nil
case <-mt.closec:
return nil, &ErrTransportClosed{}
}
}
// Dial implements Transport.
func (mt *MultiplexTransport) Dial(
addr NetAddress,
cfg peerConfig,
) (Peer, error) {
c, err := addr.DialTimeout(mt.dialTimeout)
if err != nil {
return nil, err
}
// TODO(xla): Evaluate if we should apply filters if we explicitly dial.
if err := mt.filterConn(c); err != nil {
return nil, err
}
secretConn, nodeInfo, err := mt.upgrade(c)
if err != nil {
return nil, err
}
cfg.outbound = true
p := mt.wrapPeer(secretConn, nodeInfo, cfg)
return p, nil
}
// Close implements transportLifecycle.
func (mt *MultiplexTransport) Close() error {
close(mt.closec)
if mt.listener != nil {
return mt.listener.Close()
}
return nil
}
// Listen implements transportLifecycle.
func (mt *MultiplexTransport) Listen(addr NetAddress) error {
ln, err := net.Listen("tcp", addr.DialString())
if err != nil {
return err
}
mt.listener = ln
go mt.acceptPeers()
return nil
}
func (mt *MultiplexTransport) acceptPeers() {
for {
c, err := mt.listener.Accept()
if err != nil {
// If Close() has been called, silently exit.
select {
case _, ok := <-mt.closec:
if !ok {
return
}
default:
// Transport is not closed
}
mt.acceptc <- accept{err: err}
return
}
// Connection upgrade and filtering should be asynchronous to avoid
// Head-of-line blocking[0].
// Reference: https://github.com/tendermint/tendermint/issues/2047
//
// [0] https://en.wikipedia.org/wiki/Head-of-line_blocking
go func(c net.Conn) {
var (
nodeInfo NodeInfo
secretConn *conn.SecretConnection
)
err := mt.filterConn(c)
if err == nil {
secretConn, nodeInfo, err = mt.upgrade(c)
}
select {
case mt.acceptc <- accept{secretConn, nodeInfo, err}:
// Make the upgraded peer available.
case <-mt.closec:
// Give up if the transport was closed.
_ = c.Close()
return
}
}(c)
}
}
func (mt *MultiplexTransport) cleanup(c net.Conn) error {
mt.conns.Remove(c)
return c.Close()
}
func (mt *MultiplexTransport) filterConn(c net.Conn) (err error) {
defer func() {
if err != nil {
_ = c.Close()
}
}()
// Reject if connection is already present.
if mt.conns.Has(c) {
return ErrRejected{conn: c, isDuplicate: true}
}
// Resolve ips for incoming conn.
ips, err := resolveIPs(mt.resolver, c)
if err != nil {
return err
}
errc := make(chan error, len(mt.connFilters))
for _, f := range mt.connFilters {
go func(f ConnFilterFunc, c net.Conn, ips []net.IP, errc chan<- error) {
errc <- f(mt.conns, c, ips)
}(f, c, ips, errc)
}
for i := 0; i < cap(errc); i++ {
select {
case err := <-errc:
if err != nil {
return ErrRejected{conn: c, err: err, isFiltered: true}
}
case <-time.After(mt.filterTimeout):
return ErrFilterTimeout{}
}
}
mt.conns.Set(c, ips)
return nil
}
func (mt *MultiplexTransport) upgrade(
c net.Conn,
) (secretConn *conn.SecretConnection, nodeInfo NodeInfo, err error) {
defer func() {
if err != nil {
_ = mt.cleanup(c)
}
}()
secretConn, err = upgradeSecretConn(c, mt.handshakeTimeout, mt.nodeKey.PrivKey)
if err != nil {
return nil, nil, ErrRejected{
conn: c,
err: fmt.Errorf("secrect conn failed: %v", err),
isAuthFailure: true,
}
}
nodeInfo, err = handshake(secretConn, mt.handshakeTimeout, mt.nodeInfo)
if err != nil {
return nil, nil, ErrRejected{
conn: c,
err: fmt.Errorf("handshake failed: %v", err),
isAuthFailure: true,
}
}
if err := nodeInfo.ValidateBasic(); err != nil {
return nil, nil, ErrRejected{
conn: c,
err: err,
isNodeInfoInvalid: true,
}
}
// Ensure connection key matches self reported key.
if connID := PubKeyToID(secretConn.RemotePubKey()); connID != nodeInfo.ID() {
return nil, nil, ErrRejected{
conn: c,
id: connID,
err: fmt.Errorf(
"conn.ID (%v) NodeInfo.ID (%v) missmatch",
connID,
nodeInfo.ID(),
),
isAuthFailure: true,
}
}
// Reject self.
if mt.nodeInfo.ID() == nodeInfo.ID() {
return nil, nil, ErrRejected{
addr: *NewNetAddress(nodeInfo.ID(), c.RemoteAddr()),
conn: c,
id: nodeInfo.ID(),
isSelf: true,
}
}
if err := mt.nodeInfo.CompatibleWith(nodeInfo); err != nil {
return nil, nil, ErrRejected{
conn: c,
err: err,
id: nodeInfo.ID(),
isIncompatible: true,
}
}
return secretConn, nodeInfo, nil
}
func (mt *MultiplexTransport) wrapPeer(
c net.Conn,
ni NodeInfo,
cfg peerConfig,
) Peer {
p := newPeer(
peerConn{
conn: c,
config: &mt.p2pConfig,
outbound: cfg.outbound,
persistent: cfg.persistent,
},
mt.mConfig,
ni,
cfg.reactorsByCh,
cfg.chDescs,
cfg.onPeerError,
PeerMetrics(cfg.metrics),
)
// Wait for Peer to Stop so we can cleanup.
go func(c net.Conn) {
<-p.Quit()
_ = mt.cleanup(c)
}(c)
return p
}
func handshake(
c net.Conn,
timeout time.Duration,
nodeInfo NodeInfo,
) (NodeInfo, error) {
if err := c.SetDeadline(time.Now().Add(timeout)); err != nil {
return nil, err
}
var (
errc = make(chan error, 2)
peerNodeInfo DefaultNodeInfo
ourNodeInfo = nodeInfo.(DefaultNodeInfo)
)
go func(errc chan<- error, c net.Conn) {
_, err := cdc.MarshalBinaryWriter(c, ourNodeInfo)
errc <- err
}(errc, c)
go func(errc chan<- error, c net.Conn) {
_, err := cdc.UnmarshalBinaryReader(
c,
&peerNodeInfo,
int64(MaxNodeInfoSize()),
)
errc <- err
}(errc, c)
for i := 0; i < cap(errc); i++ {
err := <-errc
if err != nil {
return nil, err
}
}
return peerNodeInfo, c.SetDeadline(time.Time{})
}
func upgradeSecretConn(
c net.Conn,
timeout time.Duration,
privKey crypto.PrivKey,
) (*conn.SecretConnection, error) {
if err := c.SetDeadline(time.Now().Add(timeout)); err != nil {
return nil, err
}
sc, err := conn.MakeSecretConnection(c, privKey)
if err != nil {
return nil, err
}
return sc, sc.SetDeadline(time.Time{})
}
func resolveIPs(resolver IPResolver, c net.Conn) ([]net.IP, error) {
host, _, err := net.SplitHostPort(c.RemoteAddr().String())
if err != nil {
return nil, err
}
addrs, err := resolver.LookupIPAddr(context.Background(), host)
if err != nil {
return nil, err
}
ips := []net.IP{}
for _, addr := range addrs {
ips = append(ips, addr.IP)
}
return ips, nil
}